scholarly journals Urban heat island intensity in London: An investigation of the impact of physical characteristics on changes in outdoor air temperature during summer

Solar Energy ◽  
2008 ◽  
Vol 82 (11) ◽  
pp. 986-998 ◽  
Author(s):  
Maria Kolokotroni ◽  
Renganathan Giridharan
Keyword(s):  
Urban Heat Island ◽  
Air Temperature ◽  
Physical Characteristics ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Outdoor Air ◽  
Urban Heat ◽  
The Impact

scholarly journals Analysis of the urban heat island intensity based on air temperature measurements in a renovated part of Budapest (Hungary)

2019 ◽  
Vol 23 (4) ◽  
pp. 277-288 ◽  
Author(s):  
Csenge Dian ◽  
Rita Pongrácz ◽  
Dóra Incze ◽  
Judit Bartholy ◽  
Attila Talamon
Keyword(s):  
Urban Heat Island ◽  
Air Temperature ◽  
Temperature Measurements ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Urban Heat

scholarly journals Opposite Effects of Aerosols on Daytime Urban Heat Island Intensity between Summer and Winter

2020 ◽  
Author(s):  
Wenchao Han ◽  
Zhanqing Li ◽  
Fang Wu ◽  
Yuwei Zhang ◽  
Jianping Guo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Urban Heat Island ◽  
Planetary Boundary Layer ◽  
Urban Areas ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Different Seasons ◽  
Urban Heat ◽  
The Impact

Abstract. The urban heat island intensity (UHII) is the temperature difference between urban areas and their rural surroundings. It is commonly attributed to changes in the underlying surface structure caused by urbanization. Air pollution caused by aerosol particles can affect the UHII by changing the surface energy balance and atmospheric thermodynamic structure. By analyzing satellite data and ground-based observations collected from 2001 to 2010 at 35 cities in China and using the WRF-Chem model, we found that aerosols have very different effects on daytime UHII in different seasons: reducing the UHII in summer, but increasing the UHII in winter. The seasonal contrast in the spatial distribution of aerosols between the urban centers and the suburbs lead to a spatial discrepancy in aerosol radiative effect (SD-ARE). Additionally, different stability of the planetary boundary layer induced by aerosol is closely associated with a dynamic effect (DE) on the UHII. SD-ARE reduces the amount of radiation reaching the ground and changes the vertical temperature gradient, whereas DE increases the stability of the planetary boundary layer and weakens heat release and exchange between the surface and the PBL. Both effects exist under polluted conditions, but their relative roles are opposite between the two seasons. It is the joint effects of the SD-ARE and the DE that drive the UHII to behave differently in different seasons, which is confirmed by model simulations. In summer, the UHII is mainly affected by the SD-ARE, and the DE is weak, and the opposite is the case in winter. This finding sheds a new light on the impact of the interaction between urbanization-induced surface changes and air pollution on urban climate.

scholarly journals Influence of the urban morphology on the urban heat island intensity: an approach based on the Local Climate Zone classification

2018 ◽  
Author(s):  
Nathalie Long ◽  
Thomas Gardes ◽  
Julia Hidalgo ◽  
Valéry Masson ◽  
Robert Schoetter
Keyword(s):  
Urban Heat Island ◽  
Urban Morphology ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Linear Regression Models ◽  
Local Climate ◽  
Urban Agglomerations ◽  
Local Climate Zones ◽  
Urban Heat ◽  
The Impact

This article presents the development and application to a set of French urban agglomerations of a method for Local Climate Zones (LCZ) attribution using the open-source language R. The LCZs classify the urban fabric at high spatial scale (such as a block of houses) according to its morphological characteristicsand land use. The LCZ classification is carried out for 42 urban agglomerations and is then related to urban heat island intensity (UHII) obtained from numerical simulations at a spatial resolution of 250m. The objective is to study the adequacy of the LCZ classification to characterise the impact of urban morphology on the UHII. The variance analysis (ANOVA) carried out confirms the highly significant relationship between LCZs and the UHII for a given urban agglomeration. For all the urban agglomerations in the sample, linear regression models show a significant correlation between the percentages of surface covered by different LCZ and the mean UHII for the time periods tested (21-23 UTC), with adjusted coefficients of determination higher than 0.40.

scholarly journals Canopy Urban Heat Island and Its Association with Climate Conditions in Dubai, UAE

Climate ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 81 ◽  
Author(s):  
Afifa Mohammed ◽  
Gloria Pignatta ◽  
Evangelia Topriska ◽  
Mattheos Santamouris
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Rural Area ◽  
Air Temperature ◽  
Negative Correlation ◽  
Wind Direction ◽  
Weather Data ◽  
Heat Island ◽  
Urban Heat ◽  
The Impact

The impact that climate change and urbanization are having on the thermal-energy balance of the built environment is a major environmental concern today. Urban heat island (UHI) is another phenomenon that can raise the temperature in cities. This study aims to examine the UHI magnitude and its association with the main meteorological parameters (i.e., temperature, wind speed, and wind direction) in Dubai, United Arab Emirates. Five years of hourly weather data (2014–2018) obtained from weather stations located in an urban, suburban, and rural area, were post-processed by means of a clustering technique. Six clusters characterized by different ranges of wind directions were analyzed. The analysis reveals that UHI is affected by the synoptic weather conditions (i.e., sea breeze and hot air coming from the desert) and is larger at night. In the urban area, air temperature and night-time UHI intensity, averaged on the five year period, are 1.3 °C and 3.3 °C higher with respect to the rural area, respectively, and the UHI and air temperature are independent of each other only when the wind comes from the desert. A negative and inverse correlation was found between the UHI and wind speed for all the wind directions, except for the northern wind where no correlation was observed. In the suburban area, the UHI and both temperatures and wind speed ranged between the strong and a weak negative correlation considering all the wind directions, while a strong negative correlation was observed in the rural area. This paper concludes that UHI intensity is strongly associated with local climatic parameters and to the changes in wind direction.

Temperature adjustments for design data for urban air conditioning design

2017 ◽  
Vol 39 (2) ◽  
pp. 211-218 ◽  
Author(s):  
Geoffrey Levermore ◽  
Stefan Vandaele ◽  
John Parkinson
Keyword(s):  
Urban Heat Island ◽  
Air Temperature ◽  
Air Conditioning ◽  
Solar Irradiation ◽  
Urban Heat Island Intensity ◽  
Wave Radiation ◽  
Urban Air ◽  
Heat Island ◽  
Urban Heat ◽  
Radiant Temperature

The urban heat island, where the urban area air temperature is higher than the nearby rural or semi-rural air temperature reference site, is now hopefully well known. The urban heat island intensity is the actual urban air temperature minus the rural air temperature. However, the “air conditioned urban heat island intensity” is measured by the air temperature sensor in an air conditioning condenser unit minus the rural air temperature. This is often different to the standard urban heat island intensity. Designers need to appreciate this difference, as it determines how the air conditioning system performs. It is most likely affected by the radiant temperature. This can also vary significantly from the rural, semi-rural radiant temperature due to the variation in solar absorptance of the urban buildings and the shading effects. Measurements have shown significant variations in the infrared temperatures over the urban areas. Calculations of the radiant absorption and long wave radiation loss also show significant differences to the rural counterparts in frequency and magnitude. This “surface urban heat island” is important for air conditioning plant situated often in areas exposed to solar irradiation. The exhaust air from the air conditioning units itself is also briefly considered. This paper examines these effects and proposes how the engineer can include for them in design. Practical application:The results of this paper will be useful for designers of buildings with air conditioning and air conditioning plant itself to assess the effect of the micro urban heat island. This micro urban heat island surrounds the air conditioning plant. The example is for London.

scholarly journals Influence of the urban morphology on the urban heat island intensity: an approach based on the Local Climate Zone classification

2018 ◽  
Author(s):  
Nathalie Long ◽  
Thomas Gardes ◽  
Julia Hidalgo ◽  
Valéry Masson ◽  
Robert Schoetter
Keyword(s):  
Urban Heat Island ◽  
Urban Morphology ◽  
Urban Heat Island Intensity ◽  
Heat Island ◽  
Linear Regression Models ◽  
Local Climate ◽  
Urban Agglomerations ◽  
Local Climate Zones ◽  
Urban Heat ◽  
The Impact

This article presents the development and application to a set of French urban agglomerations of a method for Local Climate Zones (LCZ) attribution using the open-source language R. The LCZs classify the urban fabric at high spatial scale (such as a block of houses) according to its morphological characteristicsand land use. The LCZ classification is carried out for 42 urban agglomerations and is then related to urban heat island intensity (UHII) obtained from numerical simulations at a spatial resolution of 250m. The objective is to study the adequacy of the LCZ classification to characterise the impact of urban morphology on the UHII. The variance analysis (ANOVA) carried out confirms the highly significant relationship between LCZs and the UHII for a given urban agglomeration. For all the urban agglomerations in the sample, linear regression models show a significant correlation between the percentages of surface covered by different LCZ and the mean UHII for the time periods tested (21-23 UTC), with adjusted coefficients of determination higher than 0.40.

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